Texas Instruments Corporation

Lars Jorgensen

Zigang Yang

Hardik Prakash Gandhi

Xiaohan Chen

Raul Blazquez

Jie Yang

Mohamed Farouk Mansour

Lei Ding

Hongzhi Zhao

Srinath Hosur

Nirmal Chindhu Warke

Fernando Alberto Mujica

William Louis Abbott

Roland Sperlich

Milind Anil Borkar

Prasad Chivakula

A system and method for reducing peak to average power ratio in a wireless communication system. A wireless communication system includes a radio frequency wireless transmitter that includes signal peak reduction circuitry configured to reduce peak to average power ratio of a signal to be transmitted by reducing amplitude of the signal to be transmitted that is greater than a predetermined amplitude. The signal peak reduction circuitry includes a bit inverter configured to invert a bit of a symbol identified as causing the amplitude of the signal to exceed the predetermined amplitude. The bit inverter is also configured to select the bit to invert such that inversion of the bit reduces the amplitude of the signal, and such that forward error correction in a receiver wirelessly coupled to the transmitter restores the bit to a pre-inversion value.

System and method for controlling peak to average power ratio

A digital pre-distortion component includes: a first capturing component that captures a first sample set of data; a first generating component that generates a first change matrix associated with a portion of the first sample set of data; a first memory component that stores the first change matrix; a second capturing component that captures a second sample set of data; a second generating component that generates a second change matrix associated with a portion of the second sample set of data; a second memory component that stores the second change matrix; a third capturing component that captures a third sample set of data; a third generating component that generates a third change matrix associated with a portion of the third sample set of data; a comparing component that compares the third change matrix with the first change matrix to obtain a first comparison, and compares the third change matrix with the second change matrix to obtain a second comparison; and an adapting component that adapts the digital pre-distortion component with the third sample set of data based on one of the first comparison and the second comparison.

Capture selection for digital pre-distortion adaptation and capture concatenation for frequency hopping pre-distortion adaptation

A system and method for tracking noise in a received signal uses a forward/backward Decision-Directed Phase Tracking Loop to generate a phase-noise compensation signal that removes phase noise from received single-carrier signals.

Local oscillator phase noise tracking for single carrier transmission

A method includes receiving input blocks each having multiple bits to be transmitted. The method also includes applying a first encoding scheme to a first subset of the bits in the input blocks to generate first encoded bits and applying a second encoding scheme to a second subset of the bits in the input blocks to generate second encoded bits. The second encoding scheme has lower overhead than the first encoding scheme. The method further includes generating symbols using the first and second encoded bits. The first encoded bits include two or more first bits per symbol of each output block, and the second encoded bits include one or more second bits per symbol of each output block.

Apparatus and method for multilevel coding in communication systems

A method of predistorting an input signal () for an amplifier is disclosed (FIG.). The method includes predistorting the input signal with a first set of parameters (FDPD) and a second set of parameters (CDPD) at a first time (). The first set of parameters is updated at a second time (). The second set of parameters is updated separately from the first set of parameters at a third time ().

Dual loop digital predistortion for power amplifiers

Embodiments of the invention provide a method of decoding of hexagonal constellations. The decoding methods exploit the inherent structure of the hexagonal grid to eliminate/minimize the requirements for distance computations. A constellation which has unused constellation points is received. A plurality of lookup tables is used for indicating whether a particular constellation point is used. The lookup tables are indexed using the two integers u and v. An initial estimate &#x16b; andis found. The Euclidean distance to the immediate neighbors resulting in the immediate upper and lower integers for &#x16b; andis computed. From the distance to the nearest neighbor, the log-likelihood ratio value is computed.

Hexagonal constellations and decoding same in digital communication systems

Transmitter first/second digital predistortion and first/second adaption circuitry with feedback

A method to form a CFR cancellation filter for signals with dynamic power and frequency distribution by estimating the filter at the rate required by the input signal's dynamics. For mixed mode systems (for example CDMA and LTE) the CFR is computed for each stream, and combined to form the final filter.

Crest factor reduction for signals with dynamic power and frequency distribution

This invention is a method of power amplifier digital pre-distortion which measures a current power level of the power amplifier, stores in a look up table entries consisting of a power level and a corresponding set of digital pre-distortion coefficients, selects a set of digital pre-distortion coefficients corresponding to the measured power level. If the measured current power level is near a power level index, the digital pre-distortion coefficients correspond to the power level index. If the measured current power level is greater than the maximum power level entry, the digital pre-distortion coefficients is of the maximum power level entry. If the measured current power level is less than the minimum power level entry, the digital pre-distortion is of the minimum power level entry. If the measured current power level is not near a power level index, the digital pre-distortion coefficients are an interpolation.

Power-indexed look-up table design of digital pre-distortion for power amplifiers with dynamic nonlinearities

In conventional radio frequency (RF) systems, transmitters will usually convert baseband signals to RF so as to be transmitted. As part of the conversion process, the transmitters will perform digital predistortion (DPD), which uses feedback from a power amplifier. However, there are usually mismatches between the in-phase (I) and quadrature (Q) paths within with feedback loop. Traditional IQ correction filters were ineffective at providing adequate compensation for these mismatches, but here a filter is provided that provides adequate out-of-band compensation by use of frequency selectivity.

Frequency selective IQ correction

An apparatus is provided. In the apparatus, an input to index (I2I) module maps a complex input into a real signal. A real data tap delay line is coupled to the I2I module and includes N delay-elements. A complex data tap delay line is configured to receive the complex input and includes M delay elements. A set of K of non-linear function modules is also provided. Each non-linear function module from the set has at least one real input, at least one complex input, and at least one complex output. A configurable connectivity crossbar multiplexer couples K of the N real tap delay line elements to real inputs of the set non-linear functions and couples K of the M complex tap delay line elements to complex inputs of the set non-linear function modules.

Growing community of inventors

Royal Oaks, CA, United States of America

Lars Jorgensen